The present invention relates to fluid drains for wounds such as are used for promoting healing of the wounds.
Accumulation of fluid in a closed operation field is one of the commonest surgical complications. If this fluid becomes infected, the situation may become very critical. The fluid may be evacuated by using a "passive" technique, in which only gravitational, capillary, or surface tension forces are used to move the collected fluids from the wounds, usually into the dressing. A more effective way of draining the fluid is by an "active" technique, in which a vacuum source is provided to draw the fluid under a predetermined force from the wound into a hermetically closed container. Once the vacuum is applied, the container, drain and wound form a closed system with the liquid flowing in one direction only, namely to the container.
By definition, a "fluid drain" in an active system is the tube which connects a body cavity or wound with the vacuum source and/or container.
After the fluid has entered the drain, the fluid is deprived of the protective immune mechanisms of the body, as well as of the benefit of any administered drug. Accordingly, there is nothing to prevent the bacteria from multiplying in the fluid, which acts as an "in vitro" culture. For this reason, fluid in the drain and in the container should be considered contaminated and should not be allowed to reflux into the wound.